Evaluation of an App-Delivered Psychological Flexibility Skill Training Intervention for Medical Student Burnout and Well-being: Randomized Controlled Trial

Background Physician burnout is a common problem, with onset frequently occurring during undergraduate education. Early intervention strategies that train medical students in psychological flexibility skills could support well-being and mitigate burnout risks associated with unmodifiable career stressors. There is a need for randomized controlled trials to assess effectiveness. As psychological flexibility varies contextually and among individuals, tailoring interventions may improve outcomes. Smartphone apps can facilitate individualization and accessibility, and the evaluation of this approach is an identified research priority. Objective This study aimed to evaluate the effectiveness of a stand-alone app–delivered Acceptance and Commitment Training intervention for improving medical students’ self-reported burnout, well-being, psychological flexibility, and psychological distress outcomes. We aimed to explore whether an individualized app would demonstrate benefits over a nonindividualized version. Methods This parallel randomized controlled trial was conducted with a sample of medical students from 2 Australian universities (N=143). Participants were randomly allocated to 1 of 3 intervention arms (individualized, nonindividualized, and waitlist) using a 1:1:1 allocation ratio. Individualized and nonindividualized participants were blinded to group allocation. The 5-week intervention included an introductory module (stage 1) and on-demand access to short skill training activities (stage 2), which students accessed at their own pace. Stage 2 was either nonindividualized or individualized to meet students’ identified psychological flexibility training needs. Results The mean differences in change from baseline between the intervention groups and the waitlist group were not statistically significant for burnout outcomes: exhaustion (primary; individualized: −0.52, 95% CI −3.70 to 2.65, P=.75; nonindividualized: 1.60, 95% CI −1.84 to 5.03, P=.37), cynicism (individualized: −1.26, 95% CI −4.46 to 1.94, P=.44; nonindividualized: 1.00, 95% CI −2.45 to 4.46, P=.57), and academic efficacy (individualized: 0.94, 95% CI −0.90 to 2.79, P=.32; nonindividualized: 2.02, 95% CI 0.02-4.03, P=.05). Following the intervention, the individualized group demonstrated improved psychological flexibility (0.50, 95% CI 0.12-0.89; P=.01), reduced inflexibility (0.48, 95% CI −0.92 to −0.04; P=.04), and reduced stress (−6.89, 95% CI −12.01 to 5.99; P=.01), and the nonindividualized group demonstrated improved well-being (6.46, 95% CI 0.49-12.42; P=.04) and stress (−6.36, 95% CI −11.90 to −0.83; P=.03) compared with waitlist participants. Between-group differences for the individualized and nonindividualized arms were not statistically significant. High attrition (75/143, 52.4%) was observed. Conclusions This trial provides early support for the potential benefits of Acceptance and Commitment Training for medical student well-being and psychological outcomes and demonstrates that psychological flexibility and inflexibility can be trained using a smartphone app. Although postintervention burnout outcomes were not statistically significant, improvements in secondary outcomes could indicate early risk mitigation. Replication studies with larger samples and longer-term follow-up are required, and future research should focus on improving implementation frameworks to increase engagement and optimize individualization methods. Trial Registration Australian New Zealand Clinical Trials Registry 12621000911897; https://tinyurl.com/2p92cwrw International Registered Report Identifier (IRRID) RR2-10.2196/32992

CONSORT-EHEALTH (V 1.6.1) -Submission/Publication Form The CONSORT-EHEALTH checklist is intended for authors of randomized trials evaluating web-based and Internet-based applications/interventions, including mobile interventions, electronic games (incl multiplayer games), social media, certain telehealth applications, and other interactive and/or networked electronic applications. Some of the items (e.g. all subitems under item 5 -description of the intervention) may also be applicable for other study designs.
The goal of the CONSORT EHEALTH checklist and guideline is to be a) a guide for reporting for authors of RCTs, b) to form a basis for appraisal of an ehealth trial (in terms of validity) CONSORT-EHEALTH items/subitems are MANDATORY reporting items for studies published in the Journal of Medical Internet Research and other journals / scienti c societies endorsing the checklist.
As the CONSORT-EHEALTH checklist is still considered in a formative stage, we would ask that you also RATE ON A SCALE OF 1-5 how important/useful you feel each item is FOR THE PURPOSE OF THE CHECKLIST and reporting guideline (optional).
Mandatory reporting items are marked with a red *. In the textboxes, either copy & paste the relevant sections from your manuscript into this form -please include any quotes from your manuscript in QUOTATION MARKS, or answer directly by providing additional information not in the manuscript, or elaborating on why the item was not relevant for this study.
subitem not at all important 1 2 3 4 5 essential 1a-i) Identify the mode of delivery in the title Identify the mode of delivery. Preferably use "web-based" and/or "mobile" and/or "electronic game" in the title. Avoid ambiguous terms like "online", "virtual", "interactive". Use "Internet-based" only if Intervention includes non-web-based Internet components (e.g. email), use "computer-based" or "electronic" only if o ine products are used. Use "virtual" only in the context of "virtual reality" (3-D worlds). Use "online" only in the context of "online support groups". Complement or substitute product names with broader terms for the class of products (such as "mobile" or "smart phone" instead of "iphone"), especially if the application runs on different platforms.
C l e a r s e l e c t i o n Does your paper address subitem 1a-i? * Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study 12/22/22, 11:

1a-ii) Non-web-based components or important co-interventions in title
Mention non-web-based components or important co-interventions in title, if any (e.g., "with telephone support").
C l e a r s e l e c t i o n Does your paper address subitem 1a-ii?
Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study No. There were no non-web-based components. All delivered online via app.

1a-iii) Primary condition or target group in the title
Mention primary condition or target group in the title, if any (e.g., "for children with Type I Diabetes") Example: A Web-based and Mobile Intervention with Telephone Support for Children with Type I Diabetes: Randomized Controlled Trial C l e a r s e l e c t i o n Does your paper address subitem 1a-iii? * Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study  Does your paper address subitem 1b-i? * Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Treatment description and comparator: "... 3 intervention arms (individualized, nonindividualized, and waiting list)"; "The intervention included an introductory module (Stage 1) and access to short skills training activities on demand (Stage 2). Stage 2 was either individualized to meet students' identified Psychological Flexibility training needs at each app log-in, or nonindividualized." Setting: "...conducted with a sample of medical students from two Australian universities" Blinding: Individualized and nonindividualized participants were blinded to their group 1b-ii) Level of human involvement in the METHODS section of the ABSTRACT Clarify the level of human involvement in the abstract, e.g., use phrases like "fully automated" vs. "therapist/nurse/care provider/physician-assisted" (mention number and expertise of providers involved, if any). (Note: Only report in the abstract what the main paper is reporting. If this information is missing from the main body of text, consider adding it) subitem not at all important 1 2 3 4 5 essential 1b-iii) Open vs. closed, web-based (self-assessment) vs. face-to-face assessments in the METHODS section of the ABSTRACT Mention how participants were recruited (online vs. o ine), e.g., from an open access website or from a clinic or a closed online user group (closed usergroup trial), and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment). Clearly say if outcomes were self-assessed through questionnaires (as common in web-based trials Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Trial: "...standalone app-delivered" Assessment: "...self-reported burnout outcomes" Participants: "...sample of medical students from two Australian universities..." Blinding: "Individualized and nonindividualized participants were blinded to their group allocation" 1b-iv) RESULTS section in abstract must contain use data Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "...promising support for the potential benefits of ACT training for medical student wellbeing and psychological outcomes, and demonstrates that Psychological Flexibility and Inflexibility can be trained using a smartphone app. Although postintervention burnout outcomes were not statistically significant, observed improvements in secondary outcomes could be indicative of early mitigation of risk." "Developing effective strategies to address the problem of physician burnout and its associated outcomes was an identified research priority prior to the pandemic, with a particular emphasis on early intervention strategies that could facilitate prevention... There are growing concerns that the potential endurance of these adverse mental health impacts beyond the pandemic could further diminish the resilience of medical workforces and healthcare systems, adding to the urgency of identifying and deploying effective interventions." "...medical students encounter unmodifiable demands inherent to their training and work, resulting in unavoidable contact with certain risk factors during the normal course of their careers ... Psychological and behavioral responses to demands and stressors play a role in burnout development among medical students". "Individual-level interventions have the potential to buffer against burnout and other psychological ill-health outcomes by training modifiable cognitive, emotional, and behavioural skills that can facilitate adaptive responses to unmodifiable contextual stressors". "...systematic reviews highlight the need for more rigorous studies identifying which adaptive psychological skillsets can be trained to produce optimal improvements in burnout and well-being outcomes among medical students. Psychological Flexibility is a set of adaptive cognitive and behavioral skills that is a promising intervention target" ". Does your paper address CONSORT subitem 2b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "aim ... to evaluate the effectiveness of an app-delivered ACT intervention for medical students, with respect to burnout (Exhaustion (primary outcome), Cynicism and Academic Efficacy), well-being, and Psychological Flexibility and Inflexibility outcomes. We hypothesized that medical students who engaged with either an individualized or nonindividualized version of the ACT app would demonstrate greater postintervention improvements in outcomes than those in a waiting list group, and that intervention effects would be greater for the individualized group than the nonindividualized group. We aimed to examine whether any observed postintervention improvements in burnout or well-being would be mediated by improvements in Psychological Flexibility and Inflexibility. Further, we aimed to explore whether engaging in either version of the ACT app would improve other relevant secondary psychological outcomes (stress, depression, and anxiety)." 3b) Important changes to methods after trial commencement (such as eligibility criteria), with reasons Does your paper address CONSORT subitem 3a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "This study was a 3-arm, parallel, randomized controlled trial (RCT) of a two-stage Psychological Flexibility skills training app for medical student burnout and well-being. Randomization was performed within the app using a 1:1:1 allocation ratio and a simple randomization procedure, where each student had a 1 in 3 chance of allocation to each intervention arm (individualized intervention (II); nonindividualized intervention (NI); waiting list (WL)). Allocation was blinded for participants assigned to the individualized and nonindividualized intervention groups. Blinding was not possible for the waiting list group." Does your paper address CONSORT subitem 3b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Although reminders were intended to be delivered using "push notifications", as per medical students' reported preferences, this function did not operate as intended during the study and reminders were sent by email instead."

3b-i) Bug fixes, Downtimes, Content Changes
Bug xes, Downtimes, Content Changes: ehealth systems are often dynamic systems. A description of changes to methods therefore also includes important changes made on the intervention or comparator during the trial (e.g., major bug xes or changes in the functionality or content) (5-iii) and other "unexpected events" that may have in uenced study design such as staff changes, system failures/downtimes, etc. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Although reminders were intended to be delivered using "push notifications", as per medical students' reported preferences, this function did not operate as intended during the study and reminders were sent by email instead." Does your paper address CONSORT subitem 4a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The sampling frame was students enrolled in 1st, 2nd, 4th, and 5th years of the Joint Medical Program (JMP) at the University of Newcastle (UoN) or University of New England (UNE), Australia (N=778). Students who accessed the enrolment website were assessed for eligibility, and were eligible for inclusion if they had regular access to a reliable internet connection and an electronic device compatible with app utilization (smartphone or tablet). There were no ineligibility criteria." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study only those with "regular access to ...an electronic device compatible with app utilization (smartphone or tablet)" were eligible. Open vs. closed, web-based vs. face-to-face assessments: Mention how participants were recruited (online vs. o ine), e.g., from an open access website or from a clinic, and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment), i.e., to what degree got the study team to know the participant. In online-only trials, clarify if participants were quasi-anonymous and whether having multiple identities was possible or whether technical or logistical measures (e.g., cookies, email con rmation, phone calls) were used to detect/prevent these. Does your paper address subitem 4a-ii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Students were invited to participate in a trial of a Psychological Flexibility skills training app for well-being and burnout prevention. An invitation email was sent to students' university accounts from a JMP administrative account approximately every two weeks during the recruitment period, and a member of the research team also delivered a verbal invitation at the end of online classes. Students were provided a URL and QR code that gave them access to the enrolment website (hosted on a secure online survey and database platform, REDcap: Research Electronic Data Capture; Vanderbilt University) during the recruitment period...study period for each participant commenced when they downloaded the app and created an account using their unique participant ID. All further assessment, intervention and data collection procedures were conducted within the app, which students accessed independently during the study period." subitem not at all important 1 2 3 4 5 essential 4b) Settings and locations where the data were collected 4a-iii) Information giving during recruitment Information given during recruitment. Specify how participants were briefed for recruitment and in the informed consent procedures (e.g., publish the informed consent documentation as appendix, see also item X26), as this information may have an effect on user self-selection, user expectation and may also bias results.
C l e a r s e l e c t i o n Does your paper address subitem 4a-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Students were invited to participate in a trial of a Psychological Flexibility skills training app for well-being and burnout prevention." Recruitment text can be provided if required. Does your paper address CONSORT subitem 4b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "... Joint Medical Program (JMP) at the University of Newcastle (UoN) or University of New England (UNE), Australia." "...assessment, intervention and data collection procedures were conducted within the app..."

4b-i) Report if outcomes were (self-)assessed through online questionnaires
Clearly report if outcomes were (self-)assessed through online questionnaires (as common in web-based trials) or otherwise. Does your paper address subitem 4b-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Self-report psychological outcome measures were administered at 2 time points: baseline (collected prior to randomization) and postintervention (collected 5 weeks after randomization)." (Individual self-report questionnaires are described in detail in the manuscript). 5) The interventions for each group with sufficient details to allow replication, including how and when they were actually administered subitem not at all important 1 2 3 4 5 essential Does your paper address subitem 4b-ii?

4b-ii) Report how institutional affiliations are displayed
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Not included in the manuscript. Students were informed that the study was being run by the University of Newcastle during recruitment.

5-i) Mention names, credential, affiliations of the developers, sponsors, and owners
Mention names, credential, a liations of the developers, sponsors, and owners [6] (if authors/evaluators are owners or developer of the software, this needs to be declared in a "Con ict of interest" section or mentioned elsewhere in the manuscript). Does your paper address subitem 5-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study

5-ii) Describe the history/development process
Describe the history/development process of the application and previous formative evaluations (e.g., focus groups, usability testing), as these will have an impact on adoption/use rates and help with interpreting results. Does your paper address subitem 5-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The current version of BiSi incorporated medical student feedback from a small feasibility trial of the app, with the aim of enhancing intervention relevance and engagement. This included clear explanations of what to expect during each stage of the intervention; providing progress indicators for all app components; providing earlier opportunities for personally relevant interactive learning and self-reflection (during Stage 1); and delivering content in both written and audio formats where practical (during Stage 1). We also introduced positive reinforcement components that were delivered after students completed certain activities or a certain number of activities (eg, achievement badges, experience ("XP") points). Students were asked to complete a minimum of four Stage 2 skill activities, but were also encouraged to optimize skill learning by practicing more regularly. Students were sent reminders to use the app at 6pm each day. This frequency and time was selected on the basis of feedback from the feasibility trial. Although reminders were intended to be delivered using "push notifications", as per medical students' reported preferences, this function did not operate as intended during the study and reminders were sent by email instead."

5-iii) Revisions and updating
Revisions and updating. Clearly mention the date and/or version number of the application/intervention (and comparator, if applicable) evaluated, or describe whether the intervention underwent major changes during the evaluation process, or whether the development and/or content was "frozen" during the trial. Describe dynamic components such as news feeds or changing content which may have an impact on the replicability of the intervention (for unexpected events see item 3b).
C l e a r s e l e c t i o n Does your paper address subitem 5-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study

5-iv) Quality assurance methods
Provide information on quality assurance methods to ensure accuracy and quality of information provided [1], if applicable.
C l e a r s e l e c t i o n Does your paper address subitem 5-iv?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study App use could be monitored by researcher during the trial to ensure that participants were receiving information as intended. Data was checked weekly to ensure app was functioning as planned. essential 5-v) Ensure replicability by publishing the source code, and/or providing screenshots/screen-capture video, and/or providing flowcharts of the algorithms used Ensure replicability by publishing the source code, and/or providing screenshots/screencapture video, and/or providing owcharts of the algorithms used. Replicability (i.e., other researchers should in principle be able to replicate the study) is a hallmark of scienti c reporting.
C l e a r s e l e c t i o n Does your paper address subitem 5-v?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study

5-vi) Digital preservation
Digital preservation: Provide the URL of the application, but as the intervention is likely to change or disappear over the course of the years; also make sure the intervention is archived (Internet Archive, webcitation.org, and/or publishing the source code or screenshots/videos alongside the article). As pages behind login screens cannot be archived, consider creating demo pages which are accessible without login.
C l e a r s e l e c t i o n Does your paper address subitem 5-vi?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study As per previous item, we do not have access to source code. Text and audio content for app are archived but not included here for IP reasons.

5-vii) Access
Access: Describe how participants accessed the application, in what setting/context, if they had to pay (or were paid) or not, whether they had to be a member of speci c group. If known, describe how participants obtained "access to the platform and Internet" [1]. To ensure access for editors/reviewers/readers, consider to provide a "backdoor" login account or demo mode for reviewers/readers to explore the application (also important for archiving purposes, see vi).
C l e a r s e l e c t i o n Does your paper address subitem 5-vii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "...enrolled students were provided links to download the app via the Play Store (Android) and App Store (Apple)." "The study period for each participant commenced when they downloaded the app and created an account using their unique participant ID. All further assessment, intervention and data collection procedures were conducted within the app, which students accessed independently during the study period. Intervention and assessment components were resumable, allowing students to engage with the app at their own Does your paper address subitem 5-viii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Yes. Developed by clinical psychologists.
Content: "The intervention was delivered in two stages. Stage 1: Learn the Concepts (Introductory Module) Stage 1 involved the delivery of an introductory module ("Learn the Concepts"), which was identical for the individualized and nonindividualized groups. The purpose of the module was to familiarize students with the Psychological Flexibility model and its potential benefits, and to provide a conceptual framework for understanding the Stage 2 experiential skills training activities. Students could complete the module over multiple sittings (total completion time ≈ 60 minutes, depending on individual pace). The module was composed of 7 sections (<10 mins each), presented in a fixed order. Students were required to complete each section prior to progressing to the next. Section 1 provided psychoeducation about burnout (focusing on destigmatizing burnout-related experiences and how to recognize the signs) and well-being (including the importance of choosing actions that involve consideration of personal well-being). Sections 2 to 7 provided education about each Psychological Flexibility and Inflexibility process and outlined how Psychological Flexibility skills could be implemented to support well-being and protect against burnout. While the module was primarily conceptual, interactive components encouraged self-reflection and provided opportunities to practice each skillset (eg, personal values identification, mindfulness, experiential acceptance, thought defusion, perspective-shifting, and values-based goal setting). Written and audio versions of educational content were provided, along with accompanying images. Some skill activities were presented in either written or audio format, depending on which translated best to the app-based delivery mode. Completion of the Stage 1 introductory module "unlocked" students' access to the Stage 2 on-demand skillstraining dashboard. Stage 2: Learn the Behaviours (On-Demand Skills Training) Stage 2 provided access to a library of short (3 to 8 minutes) experiential Psychological Flexibility skill activities that students could practice at any time (on-demand). Each of the six Psychological Flexibility processes had its own dashboard, where all ACT training activities for that skillset were displayed in a list (20 activities per process; 120 in total). While most activities were presented in audio format with accompanying images, some included written and interactive components." subitem not at all important 1 2 3 4 5 essential Individualization: "During Stage 2, students from both intervention groups were presented with a main dashboard ("home screen") each time they opened the app. To access the Psychological Flexibility skill activities, students selected "Practice a Skill" on the home screen and were presented with a single-item screening question ("Which of the following are you having the most difficulty with today?") to identify which Psychological Flexibility skillset might be most relevant to their training needs on that occasion (adapted from Levin et al, 2019). Students selected one of six response options, each of which corresponded to one of the six Psychological Flexibility processes: "Struggling with your feelings" (Acceptance); "Unable to do what matters to you" (Committed Action); "Stuck in your thoughts" (Defusion); "Stuck in autopilot or struggling to stay in the present moment" (Present-Moment Awareness); "Disconnected from a sense of meaning or purpose" (Values); "Stuck in stories about who you are or who you should be" (Self-as-Context).
The screening question was used to tailor the intervention to the training needs of students in the individualized group. Upon completion of the screening question, participants in the individualized group were presented with the dashboard corresponding to the Psychological Flexibility skillset they identified having the most difficulty with on that occasion (eg, if a student reported feeling disconnected from a sense of meaning or purpose, the app displayed the values dashboard). This allowed students in the individualized group to practice a skill targeted to the area of identified need each time they accessed the app. For the nonindividualized group, students' responses to the screening question had no impact on the skillset they received training in. After responding to the screening question, students in the nonindividualized group were presented with one of the six Psychological Flexibility dashboards at random (simple randomization; each process had an equal chance of selection). Once students were given access to a Psychological Flexibility dashboard, they could practice any activity from that skillset, either by choosing from the list or allowing the app to select for them. The latter involved a simple randomization process, where each activity had an equal chance of selection (1 in 20). Upon completion of an activity, students had the option to complete another within the same Psychological Flexibility skillset. If they selected "yes" these steps were repeated until the participant elected to discontinue." Persuasive features: "The current version of BiSi incorporated medical student feedback from a small

5-ix) Describe use parameters
Describe use parameters (e.g., intended "doses" and optimal timing for use). Clarify what instructions or recommendations were given to the user, e.g., regarding timing, frequency, heaviness of use, if any, or was the intervention used ad libitum.
C l e a r s e l e c t i o n Does your paper address subitem 5-ix?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Students were asked to complete a minimum of four Stage 2 skill activities, but were also encouraged to optimize skill learning by practicing more regularly." "Adherence to the individualized and nonindividualized intervention arms was defined as the completion of all Stage 1 components and engagement in at least four skill activities during Stage 2. This level of adherence provided students the opportunity to learn about, and practice, each of the Psychological Flexibility processes (Stage 1) and practice the skills a few times in their everyday lives (Stage 2). " subitem not at all important 1 2 3 4 5 essential feasibility trial of the app, with the aim of enhancing intervention relevance and engagement. This included clear explanations of what to expect during each stage of the intervention; providing progress indicators for all app components; providing earlier opportunities for personally relevant interactive learning and self-reflection (during Stage 1); and delivering content in both written and audio formats where practical (during Stage 1). We also introduced positive reinforcement components that were delivered after students completed certain activities or a certain number of activities (eg, achievement badges, experience ("XP") points). Students were asked to complete a minimum of four Stage 2 skill activities, but were also encouraged to optimize skill learning by practicing more regularly. Students were sent reminders to use the app at 6pm each day. This frequency and time was selected on the basis of feedback from the feasibility trial. Although reminders were intended to be delivered using "push notifications", as per medical students' reported preferences, this function did not

5-x) Clarify the level of human involvement
Clarify the level of human involvement (care providers or health professionals, also technical assistance) in the e-intervention or as co-intervention (detail number and expertise of professionals involved, if any, as well as "type of assistance offered, the timing and frequency of the support, how it is initiated, and the medium by which the assistance is delivered". It may be necessary to distinguish between the level of human involvement required for the trial, and the level of human involvement required for a routine application outside of a RCT setting (discuss under item 21 -generalizability).
C l e a r s e l e c t i o n

Does your paper address subitem 5-x?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Does your paper address CONSORT subitem 6a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Yes. "Self-report psychological outcome measures were administered at 2 time points: baseline (collected prior to randomization) and postintervention (collected 5 weeks after randomization)." Detailed information is provided re: how each outcome was assessed and the measures used. "Behavioral engagement data and subjective intervention feedback was collected from participants throughout the study." Detail provided in manuscript.
6a-i) Online questionnaires: describe if they were validated for online use and apply CHERRIES items to describe how the questionnaires were designed/deployed Copy and paste relevant sections from manuscript text "Students were invited to submit feedback about their experience of using the app via a form presented halfway through Stage 1. The feedback form was also accessible via the main dashboard. During Stage 2, participants rated whether they "liked" each skill activity they practiced, using a single-item binary measure ("thumbs up" (like) or "thumbs down" (dislike) icon). Participants were invited to report concerns or harms experienced during the study using contact links provided within the app and via email communications (eg, daily reminders)." Does your paper address CONSORT subitem 6b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Although reminders were intended to be delivered using "push notifications", as per medical students' reported preferences, this function did not operate as intended during the study and reminders were sent by email instead. " 7a-i) Describe whether and how expected attrition was taken into account when calculating the sample size

7b) When applicable, explanation of any interim analyses and stopping guidelines
Does your paper address subitem 7a-i?
Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "[power] analysis indicated that a sample of 117 participants would provide sufficient power (80%) to detect a clinically meaningful effect size (0.65 standard deviations) between either intervention arm and the control arm in the primary outcome (Exhaustion), measured by the MBI-GS(S)), with a Type I error rate of 5%. We aimed to recruit up to 153 participants to provide a 30% margin for attrition." Does your paper address CONSORT subitem 7b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Does your paper address CONSORT subitem 8a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Randomization was performed within the app using a 1:1:1 allocation ratio and a simple randomization procedure, where each student had a 1 in 3 chance of allocation to each intervention arm (individualized intervention (II); nonindividualized intervention (NI); waiting list (WL))." 9) Mechanism used to implement the random allocation sequence (such as sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned 10) Who generated the random allocation sequence, who enrolled participants, and who assigned participants to interventions Does your paper address CONSORT subitem 8b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Functional limitations of the app meant that it was not possible to stratify randomization by participant baseline characteristics." Does your paper address CONSORT subitem 9? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Does your paper address CONSORT subitem 10? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Information provided in item 8a 11a-i) Specify who was blinded, and who wasn't Specify who was blinded, and who wasn't. Usually, in web-based trials it is not possible to blind the participants [1, 3] (this should be clearly acknowledged), but it may be possible to blind outcome assessors, those doing data analysis or those administering cointerventions (if any Does your paper address subitem 11a-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Allocation was blinded for participants assigned to the individualized and nonindividualized intervention groups. Blinding was not possible for the waiting list group." 11a-ii) Discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator" Informed consent procedures (4a-ii) can create biases and certain expectations -discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator".

11b) If relevant, description of the similarity of interventions
(this item is usually not relevant for ehealth trials as it refers to similarity of a placebo or sham intervention to a active medication/intervention)

Does your paper address subitem 11a-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study See 11a-i. " Students were informed that there were two intervention groups, and that the only difference was the way skill activities were selected for them by the app." Does your paper address CONSORT subitem 11b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study 12a) Statistical methods used to compare groups for primary and secondary outcomes NPT: When applicable, details of whether and how the clustering by care providers or centers was addressed Does your paper address CONSORT subitem 12a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "...intention-to-treat analysis..." "Differences between intervention arms were assessed using linear mixed regression models for primary... and secondary outcomes... separate model was estimated for each outcome variable. The models included fixed categorical effects for time (baseline as the referent), intervention group, the interaction between intervention and time, and selfreported baseline participant characteristics that were imbalanced after randomization...

12a-i) Imputation techniques to deal with attrition / missing values
Imputation techniques to deal with attrition / missing values: Not all participants will use the intervention/comparator as intended and attrition is typically high in ehealth trials. Specify how participants who did not use the application or dropped out from the trial were treated in the statistical analysis (a complete case analysis is strongly discouraged, and simple imputation techniques such as LOCF may also be problematic [4]).
C l e a r s e l e c t i o n Does your paper address subitem 12a-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "This study adopted an intention-to-treat analysis, which included data collected from all participants randomized into a study group. Each participant's data was analyzed based on the study group they were randomized to, irrespective of their degree of intervention engagement or whether they met adherence criteria. This approach maintains randomization benefits and minimizes bias when assessing intervention efficacy" Does your paper address CONSORT subitem 12b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Baseline participant demographic and psychological characteristics were compared between 1) those who were lost to follow-up at any point during the study versus those who were not, and 2) those who met intervention adherence criteria versus those who did not, using chi-square tests for categorical variables and independent sample Student's t-tests for continuous variables (Welch's t-tests used where assumption of equal variance was violated). Average rates of engagement during Stage 2 were compared between the individualized and nonindividualized groups using independent Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Participation was voluntary, confidential, and independent from students' academic program. Those who elected to participate registered their consent using an e-consent process. "

X26-iii) Safety and security procedures
Safety and security procedures, incl. privacy considerations, and any steps taken to reduce the likelihood or detection of harm (e.g., education and training, availability of a hotline) C l e a r s e l e c t i o n

Does your paper address subitem X26-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Participants were invited to report concerns or harms experienced during the study using contact links provided within the app and via email communications (eg, daily reminders)." 13a) For each group, the numbers of participants who were randomly assigned, received intended treatment, and were analysed for the primary outcome NPT: The number of care providers or centers performing the intervention in each group and the number of patients treated by each care provider in each center 13b) For each group, losses and exclusions after randomisation, together with reasons Does your paper address CONSORT subitem 13a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "A sample of 143 medical students enrolled in the study." "participants who proceeded to randomization and were included in efficacy analyses (n=108)" See Tables 1 and 2 for number of participants per intervention group, number who completed post-intervention assessments, and number at each center. Does your paper address CONSORT subitem 13b? (NOTE: Preferably, this is shown in a CONSORT flow diagram) * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Provided in Figure 1 (participant flow) and Appendix 2 and 4. "Only one participant formally withdrew, citing perceived personal irrelevance of baseline outcome measures."

13b-i) Attrition diagram
Strongly recommended: An attrition diagram (e.g., proportion of participants still logging in or using the intervention/comparator in each group plotted over time, similar to a survival curve) or other gures or tables demonstrating usage/dose/engagement.

14a) Dates defining the periods of recruitment and follow-up
Does your paper address subitem 13b-i?
Copy and paste relevant sections from the manuscript or cite the gure number if applicable (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Not included in this manuscript. However, adherence/engagement rates at key stages of intervention by group is provided in Appendix 4.
Does your paper address CONSORT subitem 14a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Does your paper address subitem 14a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The study period "unintentionally coincided with a mandated lockdown due to a regional Covid-19 outbreak." Does your paper address CONSORT subitem 14b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The trial did not stop early Does your paper address CONSORT subitem 15? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study

16-i) Report multiple "denominators" and provide definitions
Report multiple "denominators" and provide de nitions: Report N's (and effect sizes) "across a range of study participation [and use] thresholds" [1], e.g., N exposed, N consented, N used more than x times, N used more than y weeks, N participants "used" the intervention/comparator at speci c pre-de ned time points of interest (in absolute and relative numbers per group). Always clearly de ne "use" of the intervention.
C l e a r s e l e c t i o n Does your paper address subitem 16-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Information available in Figure 1,

16-ii) Primary analysis should be intent-to-treat
Primary analysis should be intent-to-treat, secondary analyses could include comparing only "users", with the appropriate caveats that this is no longer a randomized sample (see 18-i).
C l e a r s e l e c t i o n Does your paper address subitem 16-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "This study adopted an intention-to-treat analysis, which included data collected from all participants randomized into a study group. Each participant's data was analyzed based on the study group they were randomized to, irrespective of their degree of intervention engagement or whether they met adherence criteria. This approach maintains randomization benefits and minimizes bias when assessing intervention efficacy" Does your paper address CONSORT subitem 17a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study This information is provided in Table 2.

17a-i) Presentation of process outcomes such as metrics of use and intensity of use
In addition to primary/secondary (clinical) outcomes, the presentation of process outcomes such as metrics of use and intensity of use (dose, exposure) and their operational de nitions is critical. This does not only refer to metrics of attrition (13-b) (often a binary variable), but also to more continuous exposure metrics such as "average session length". These must be accompanied by a technical description how a metric like a "session" is de ned (e.g., timeout after idle time) [1] (report under item 6a 17b) For binary outcomes, presentation of both absolute and relative effect sizes is recommended Does your paper address subitem 17a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Information provided in Appendix 4. Duration of intervention components described in Method. See also response to 5-ix.
Does your paper address CONSORT subitem 17b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Students in the intervention groups "liked" 87% (222/255) of the skill activities completed during Stage 2, and "disliked" 13% (33/255)."

18) Results of any other analyses performed, including subgroup analyses and
adjusted analyses, distinguishing pre-specified from exploratory subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 18? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Results for all outcomes are reported. Exhaustion is identified as the primary outcome. All other outcomes are secondary, as explained throughout the manuscript.

18-i) Subgroup analysis of comparing only users
A subgroup analysis of comparing only users is not uncommon in ehealth trials, but if done, it must be stressed that this is a self-selected sample and no longer an unbiased sample from a randomized trial (see 16-iii Does your paper address subitem 18-i? Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Subgroup analyses were not conducted in this study.
Does your paper address CONSORT subitem 19? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study

19-i) Include privacy breaches, technical problems
Include privacy breaches, technical problems. This does not only include physical "harm" to participants, but also incidents such as perceived or real privacy breaches [1], technical problems, and other unexpected/unintended incidents. "Unintended effects" also includes unintended positive effects [2].

Does your paper address subitem 19-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study

Does your paper address subitem 19-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Participants who utilized the in-app feedback form (n=15) reported finding the intervention content interesting and helpful in relation to their psychological health and well-being. Some reported that, despite finding the app helpful, time was a key barrier to engagement. Other feedback included requests for additional usability functions, such as dark mode and written versions of activities that were only presented in audio format. Students in the intervention groups "liked" 87% (222/255) of the skill activities completed during Stage 2, and "disliked" 13% (33/255). Does your paper address subitem 22-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study For example: "Based on the existing literature, we anticipated that training medical students in Psychological Flexibility skills would lead to improved burnout". "Since Psychological Flexibility is associated with well-being, we expected that engaging in an ACT intervention would improve this outcome among medical students." "Although medical students who engaged in either the individualized or nonindividualized intervention demonstrated improvements in at least one psychological outcome compared with those in the waiting list group, unlike Levin et al. (2019), we did not observe statistically significant differences between the two intervention groups for any of the outcomes assessed. However, in addition to being underpowered to detect these effects, it is possible that methodological factors obfuscated our ability to evaluate the true potential treatment utility of individualized over nonindividualized Psychological Flexibility skills training." Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study For example: "Replication and longitudinal studies are needed to further clarify the role that Psychological Flexibility and Inflexibility interventions (eg, ACT) may play in improving well-being and mitigating the adverse impacts of stress within the medical profession, including burnout. Although we did not observe differences in efficacy between the individualized and nonindividualized versions of the app, the individualized intervention was beneficial to a greater number of outcomes. Further research addressing the methodological limitations observed in the current study could progress key Psychological Flexibility literature goals related to individual heterogeneity and intervention precision. "

20-i) Typical limitations in ehealth trials
Typical limitations in ehealth trials: Participants in ehealth trials are rarely blinded. Ehealth trials often look at a multiplicity of outcomes, increasing risk for a Type I error. Discuss biases due to non-use of the intervention/usability issues, biases through informed consent procedures, unexpected events.
C l e a r s e l e c t i o n Does your paper address subitem 20-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Generalizability of the current findings may be limited, given the predominantly nonindigenous Australian sample with a slight skew towards female participants. " Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study For example: "Successful burnout prevention and well-being interventions likely require a combination of organizational and individual resource-building strategies [1]. While the current app was delivered within an organizational context and supported by the universities in which it was implemented, intentional efforts were made to distance the intervention from students' university programs to ensure that they did not feel compelled to participate. However, increased organizational efforts to support participation in a psychological skill development app may have an important impact on normalizing and prioritizing commitment to personal well-being during the early and formative stages of a medical career. Given the preliminary support for the benefits of this ACT intervention, future implementation studies might examine whether embedding the app into broader university-based burnout and well-being initiatives strengthens adherence and https://docs.google.com/forms/d/e/1FAIpQLSfZBSUp1bwOc_OimqcS64RdfIAFvmrTSkZQL2-3O8O9hrL5Sw/viewform?fbzx=-186947723883213169&hl=en 89/99

X27) Conflicts of Interest (not a CONSORT item)
subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 25? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study This research project was funded by the Centre for Rehab Innovations and the Priority Research Centre for Stroke and Brain Injury at the University of Newcastle.

X27-i) State the relation of the study team towards the system being evaluated
In addition to the usual declaration of interests ( nancial or otherwise), also state the relation of the study team towards the system being evaluated, i.e., state if the authors/evaluators are distinct from or identical with the developers/sponsors of the intervention. Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study No conflicts of interest declared.
As a result of using this checklist, did you make changes in your manuscript? * What were the most important changes you made as a result of using this checklist?
Made changes following original round, but this is the second time I have completed the checklist for this manuscript (following peer review). How much time did you spend on going through the checklist INCLUDING making changes in your manuscript

* 3 hours
As a result of using this checklist, do you think your manuscript has improved? *

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